Tucson Electric Power 10-Q 2006 Q3 Quarterly report

Exhibit 12(a)

UniSource Energy Corporation

Computation of Ratio of Earnings to Fixed Charges

	9 Months Ended		12 Months Ended				12 Months Ended(2)
	Sept. 30			Sept. 30			Dec. 31,			Dec. 31,			Dec. 31,			Dec. 31,			Dec. 31,
	2006			2006			2005			2004			2003			2002			2001
	- Thousands of Dollars -						- Thousands of Dollars -
Fixed Charges:
Interest on Long-Term Debt	$	56,747		$	75,411		$	76,762		$	80,968		$	80,844		$	65,620		$	68,678
Other Interest (1)		6,876			7,527			3,153			1,947			3,709			2,123			1,287
Interest on Capital Lease Obligations		55,047			74,920			79,098			85,912			84,080			87,801			90,559
Total Fixed Charges		118,670			157,858			159,013			168,827			168,633			155,544			160,524
Net Income		55,023			77,085			46,144			45,919			113,941			34,928			63,839
Less:
Discontinued Operations - Net of Tax		(2,669	)		(3,731	)		(5,483	)		(5,063	)		(7,472	)		(12,919	)		(9,926	)
Accounting Change - Net of Tax		-			(626	)		(626	)		-			67,471			-			470
Net Income from Continuing Operations		57,692			81,442		��	52,253			50,982			53,942			47,847			73,295
Add (Deduct):
(Income) Losses from Equity Investees		(208	)		(2,599	)		(2,113	)		(7,121	)		3,051			3,047			10,748
Income Taxes		38,630			56,770			37,623			37,186			16,531			26,432			55,616
Total Fixed Charges		118,670			157,858			159,013			168,827			168,633			155,544			160,524
Total Earnings before Taxes
and Fixed Charges	$	214,784		$	293,471		$	246,776		$	249,874		$	242,157		$	232,870		$	300,183
Ratio of Earnings to Fixed Charges		1.810			1.859			1.552			1.480			1.436			1.497			1.870

(1) Excludes recognition of Allowance for Borrowed Funds Used During Construction.

(2) The information previously reported has been reclassified for the discontinued operations of Global Solar, Inc.